borderbotton($color)
  position relative
  &::after
    content ''
    display block
    position absolute
    left 0
    bottom 0
    width 100%
    border-bottom 1px solid $color
    @media (-webkit-min-device-pixel-ratio 1.5),(min-device-pixel-ratio 1.5)
      transform scaleY(0.7)
    @media (-webkit-min-device-pixel-ratio 2),(min-device-pixel-ratio 2)
      transform scaleY(0.5)

bgImg($url)
  background-image url('../assets/' + $url + '@2x.png')
  background-size cover
  @media (-webkit-min-device-pixel-ratio 3),(min-device-pixel-ratio 3)
    background-image url('../assets/' + $url + '@3x.png')
    background-size cover